Long noncoding RNA NEAT1 suppresses sorafenib sensitivity of hepatocellular carcinoma cells via regulating miR-335-c-Met.

Abstract

To investigate the role of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating sorafenib (Sora) sensitivity of hepatocellular carcinoma (HCC) cells and possible signaling pathways. HCC cell lines and tumor tissue were quantified for NEAT1 expression by quantitative polymerase chain reaction (qPCR). Following shRNA (short hairpin RNA) knockdown of NEAT1, cell viability, apoptosis, and related protein expression were measured after drug treatment. The downstream target of NEAT1, including miR-335 and c-Met was studied using a combination of luciferase binding assay, gene knockdown/overexpression, western blot analysis, and cell viability/apoptosis assay. Cancer cells with NEAT1 knockdown were transplanted onto nude mice for in vivo tumorigenesis assay. Silencing of NEAT1 in HCC cells facilitated Sora sensitivity by enhancing drug-induced apoptosis, and led to smaller tumor size on nude mice. Mechanistic study suggested that miR-335 was negatively regulated by NEAT1, and miR-335 further suppressed c-Met-Akt pathway, whose activation caused drug resistance of HCC cells. The knockdown of miR-335, or overexpression of c-Met, all remarkably abolished the proapoptotic effect of NEAT1 knockdown in HCC cells. lncRNA NEAT1 mediates Sora resistance of HCC cells by suppressing miR-335 expression, and disinhibition on c-Met-Akt signaling pathway. Our results provide potency of NEAT1 as the biomarker for drug resistant HCC and possible treating targets.